Fast growth of the pervasive computing and handheld/communication industry has generated exploding demand for high capacity nonvolatile solid-state data storage devices. Current technology like flash memory has several drawbacks such as slow access speed, limited endurance, and the integration difficulty. Flash memory (NAND or NOR) also faces significant scaling problems.
Resistive sense memories are promising candidates for future nonvolatile and universal memory by storing data bits as either a high or low resistance state. One such memory, magnetic random access memory (MRAM), features non-volatility, fast writing/reading speed, almost unlimited programming endurance and zero standby power. The basic component of MRAM is a magnetic tunneling junction (MTJ). MRAM switches the MTJ resistance by using a current induced magnetic field to switch the magnetization of MTJ. As the MTJ size shrinks, the switching magnetic field amplitude increases and the switching variation becomes more severe. Memories that include magnetic tunnel junctions which have their magnetization switchable by spin torque, caused by a current induced magnetic field, are commonly referred to as spin torque random access memory (STRAM).
At least because of their small size, it is desirous to use resistive sense elements in many applications, such as magnetic hard disk drive read heads, magnetic sensors, and non-volatile random access memory. Their small size, however, presents some difficulties. Improvements and developments in resistive sense elements and their manufacture, including enhanced magnetic stability, are always desired.